It’s quite amazing that 2015 has gone by so quickly – hard to believe I am writing the December editorial. It’s been a busy year obviously – and the Journal has seen some new developments FirstView is now up and running – this means that, as soon as each individual paper is completed, it will appear online although not in print until the next available issue. This means for authors, that they get their paper out in public much more quickly than they previously did, where all papers had to wait until the print copy was prepared. Authors increasingly ask me when their paper will be ready once it has been finalised – so now that time period is much shorter. The Journal runs about six months ahead of itself (I am currently working on papers for March issue) which is fairly typically for print copy based publications.

Other Journal news – I had a major ‘clear out’ of papers that were languishing on the submission system waiting for final revisions to be made by authors – which is now done and we can get back to our regular turnover. Please note that papers that have sat in the system awaiting revision will now be given a deadline for completion or will be removed from the system – a bit of housekeeping from our side if you like.

As for events in 2015, the Poultry Science Association was kind enough to invite me to their meeting in July. Dr Mamduh Sifri retired formally – somewhat of an end to an era as he is such a major figure in the avian science world and will be missed for his work, research, energy and kindness. The sad loss of Professor Gordon Rosen in August, after a short illness was a great loss to many people – both commercial and in research. There will be a memorial evening for Gordon at the UK Spring Branch meeting at Chester in April – and information will be posted on their website as organisation progresses.

Of course, looking to the future, the major event in the poultry world next year will be the Congress in Beijing. I trust many of you are already planning to attend and I look forward to seeing you there.

Dr Lucy Waldron

Editor

The concept of ‘sustainability’ or ‘sustainable development’ is multi-dimensional, encompassing economic, environmental, social, and institutional governance aspects. The theoretical framework for this article on sustainability in poultry production is built on this multi-dimensional understanding of the concept, acknowledging that it is complex and contested. It is challenging to analyse or discuss the sustainability of one single sector within agriculture, because this sector is part of a global food system, and a systems approach is necessary. This article gives examples of elements which link to one or more of the four aspects, e.g., pollution and antibiotic use, biodiversity (environmental aspects), conditions for farm workers and animal welfare (social aspects), governance of the food chain (institutional aspects), and the development of poultry from a valuable food to a cheap staple food throughout major parts of the world (economic aspects). There are numerous potential pathways for sustainable development of poultry production. Poultry are living, sentient animals that can be well integrated into many different types of urban and rural farming systems, where they benefit from and contribute to such systems and to the livelihood of households around the globe, with special emphasis on women. Furthermore, local production provides potential for production with minimum transport and, concomitantly, minimum usage of fossil fuels. Among the terrestrial animals, poultry has the best conversion rate of feed to human food and the smallest environmental footprint in terms of energy and water use per kg meat or eggs produced.

Composting is the enhanced biological decomposition of organic materials in a primarily aerobic environment. During the process, microorganisms break down organic materials to stable, usable organic substances in a process which consumes oxygen and releases heat, water, and CO2. Under controlled conditions, the composting process is described in two phases, primary and secondary. Chemical and physical properties of the raw wastes affect the rate of composting. Particle size and surface area of the waste material influence the type of microorganisms involved and the degree of biological activity in the composting process. Composting allows safe disposal of birds and manure and reduces environmental degradation. Composting of poultry manure and dead birds is still a debatable topic, however, with some scientists in favour of composting due to its overwhelming advantages while others are against composting due to certain disadvantages/environmental hazards. The present article is an effort to encompass the overall composting process, its applications as well as troubleshooting various associated issues.

Organic acids are naturally-occurring, carbon containing compounds with acidic properties. Organic acids have antimicrobial activity, which has been utilised for centuries to control undesirable microorganisms in foodstuffs. Interest in the use of organic acids for farmed animals has increased primarily as a result of the desire to reduce foodborne pathogens and the decreasing global acceptance of the use of antibiotics as growth promoters (AGPs). Whilst acidity (or pH) has a profound effect on microbes, it is the undissociated portion of an organic acid that is believed to contribute significantly to their antimicrobial effect. This review focuses on the microorganism, its ability to tolerate acid stress, the effect of organic acids and considers key work behind the application of organic acids in the global poultry industry. This application focussed initially on controlling Salmonella in the feed and intestine of poultry. More recent work with organic acids has highlighted the apparent wider benefits to poultry intestinal health, from improvements in gut morphology to regulation of bacterial virulence gene expression, which are outlined in this review.

The restricted use of antibiotics in the poultry sector has greatly enhanced the search for environment-friendly alternatives and complementary therapeutic approaches to manage infectious diseases in poultry. Cytokines, as natural immune-modulators, offer alternatives to conventional chemical-based therapeutics. Cytokine usage is becoming more feasible in poultry due to recent advancements in the field of immunology and vaccination, leading to the identification and cloning of avian cytokine genes. Existing adjuvants for poultry vaccines can have deleterious side-effects on the health and products of poultry and a subsequent reduction in profits. Therefore, alternative adjuvants must be developed to enhance the impact of vaccination. The use of cloned cytokines as adjuvants in poultry is attracting attention after the identification of new cytokine genes in chicken. Hence, cytokines may be used as therapeutics and vaccine adjuvants for enhancing immune response during infection and vaccination. This review focuses on the recent advancements in the application of avian cytokines as therapeutics or vaccine adjuvants.

The broiler chick's gastrointestinal tract undergoes significant morphological and physiological changes during the first days after hatch. These changes occur mostly because birds switch from a diet based on fatty acids from the yolk sac to a diet based on carbohydrates, provided by commercial feeds, often formulated with corn and soya bean meal. In ovo feeding techniques enable the study of the early adaptation of the avian gastrointestinal tract, such as supplementation with carbohydrates during embryonic development. This procedure consists of inoculation into the amniotic fluid through a hole in the egg shell near the air-chamber during late embryonic growth. The hatching process requires large supply of energy to the muscles, and in ovo feeding has the objective of providing extra energy in order to avoid glycogen store reductions, which are needed during the first days after hatch. However, published reports have shown that in ovo manipulation can reduce incubation yield, mostly when applied during the beginning of embryonic development. The best results of in ovo feeding were found when supplementation was with carbohydrates.

The aim of this review is to discuss the use of microalgae as a feed ingredient in poultry nutrition. Microalgae are unicellular, photosynthetic aquatic plants. They are introduced to poultry diets mainly as a rich source of n-3 long chain polyunsaturated fatty acids, including docohexaenoic and eicosapentaenoic acid, but they can also serve as a protein, microelement, vitamin and antioxidants source, as well as a pigmentation agent for skin and egg yolks. The majority of experiments have shown that microalgae, mainly Spirulina and Chlorella sourced as a defatted biomass from biofuel production, can be successfully used as a feed ingredient in poultry nutrition. They can have beneficial effects on meat and egg quality, i.e. via an increased concentration of n-3 polyunsaturated fatty acids and carotenoids, and in regards to performance indices and immune function. Positive results were obtained when fresh microalgae biomass was used to replace antibiotic growth promoters in poultry diets. In conclusion, because of their chemical composition, microalgae can be efficiently used in poultry nutrition to enhance the pigmentation and nutritional value of meat and eggs, as well as partial replacement of conventional dietary protein sources.

The aim of this review is to discuss aspects of poultry meat quality which are influenced by supplementing the bird's diets with plant extracts. Nutritional approaches are often more effective than direct addition of the additive to meat since the compound is preferably deposited where it is most needed. Physical qualities of broiler meat, including pH and colour, is of major importance, since broiler chicken meat is nowadays usually consumed as cut up pieces or processed products. Sensory and proximate meat quality should be taken into consideration because this allows manufacturers to identify, understand and respond to consumer preferences more effectively. Lipids including cholesterol are an important component of meat and contribute to several desirable sensory characteristics of meat and meat products. Amongst meat products, poultry meat is considered to be more prone to the development of oxidative rancidity compared to red meat. This is explained by the higher content of phospholipids in poultry meat. The available literature is limited regarding changes in meat quality due to the effect of medicinal plants, especially in poultry, however this review will summarise the results of the investigations that have been published to date.

Spices, herbs and medicinal plants as a feed supplements present promising alternatives to antibiotic growth promoters due to their high content of bioactive substances. A large number of experiments have confirmed a wide range of activities of spices in poultry nutrition such as stimulation of feed intake, antimicrobial, antioxidative and coccidiostat stimulation, increase of body weight gain, lowering the mortality rate and improvement of the blood and tissue lipid profile. The present paper gives a review on the characteristics of hot red pepper and its mode of action in broilers nutrition.

The poultry sector is an important and vibrant segment of agriculture in Pakistan with a significant contribution to the national GDP (1.3%). Commercial poultry production in Pakistan started in the 1960's and has been providing a significant portion of daily proteins to the Pakistani population ever since. During its evolution the industry enjoyed promotional policies of the Government, but has faced several challenges such as disease outbreaks and retail price fluctuations. Despite its important role in the country's economy, not a single scientific study is available on its evolutionary history. The data available in this regard are scattered and lack reliability. This review is an effort to encompass the history of the overall growth of the poultry industry in Pakistan, its present status (2012 statistics) and future directions and challenges. This article may serve as the basic source of information on Pakistan's poultry industry achievements. It will also guide poultry experts and policy makers for developing strategic planning for further growth of the industry.

With the continued increases in broilers production, the negative impact of environmental conditions on birds has attracted increasing public awareness and concern. Heat stress is one of the most important environmental stressors challenging broiler production world-wide. The detrimental effects of heat stress on broilers range from reduced growth to decreased quality of broiler products. This review focuses on the available scientific evidence for the impact of heat stress in broiler production, with emphasis on performance, physiological and biochemical effects, muscle oxidation, and meat quality.

The World’s Poultry Science Journal is indebted to Prof J.A. Castello, Prof D.K. Flock, Dr D. Grastilleur, Dr S. Cherepanov and Prof N. Yang for the translations of these summaries.